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How does your log template and trend display settings look like?

Do you have any log stretching beyond 1 month?

The Log Configuration aspect has a Status tab; use it to probe the hierarchy of logs for their content. Can you find any older data than one month (the default is to read the 1000 most recent values stored, but can be changed to e.g. the 10 oldest values using the Settings button)?

Also; by using trend treatment Momentary or ExtMomentary you also lock down the seamless engine to only prefer primary logs. By selecting TimeAverage treatment you unlock the seamless engine to also consider secondary logs.

Unfortunately do some library developers code their trends with Momentary or ExtMomentary treatment; if such library is locked you will not be able to use its trends to view more than what the primary log contain.

Momentary has another limitation; it paints EVERY value found in the log thus rapidly burning up the 86400 values that is the cap for any trend request. 1 day of 1s raw data = 86400 values; likely a lot of them will get same X,Y coordinates and is painted "redundant".

ExtMomentary paints exactly as Momentary, but uses a compression algorithm so that a straight vertical line is painted between the min and max values for a multitude of values ending up on the same sample interval. This saves a lot of points and will make much more wise use of the 86400 values.

1.Historical data is saved in connectiviy server by Basic Historian as default in 800XA Basic system.If you have Information Manager installed then it takes data from historical logs using OPC's HDA Standard protocol and store it in itself.

2.Basic Hostory service is responsible for acquiring and logging the data.It takes data from opc server.

3.It is not possible to archive the data without installing additional IM sever. There is a limitation to basic setup.Refer Image attached.

Though you can increase the duration of stored data a bit by increasing sampling time.

Pl be informed that this works on FIFO(First in First out) cycle. When the memory i full, it will replace oldest information with newest one.